Various systems have been used to monitor a moving target by using camera. One of such systems includes a system that uses fixed cameras, each of which is defined with a region that can be monitored. In this system, in view of the moving direction of the moving target, the camera used for monitoring and the monitor mode of each camera are switched, so that the moving target can be monitored.
However, in a system using such a fixed camera, it may be impossible to monitor the moving target sufficiently in an environment where the blind spot dynamically changes.